Welcome
The most important thing for a bunny is a consistent routine. So if you have a 12 hour schedule, try to do the same things at the same times daily, whether you are there or not. Play together first thing as you get ready, then leave breakfast before you go. With a shift that long, I would suggest two sources of water – like two crocks in case one gets emptied or spills – and a very full hay bin. Bunny will graze slowly, so will get used to a later supper of greens if there is enough hay all shift. He will also sleep much of the day, so will be ready for play as soon as you get home.
I don,t know about free range all that time, though. Consider an extra large X-Pen, or maybe two clamped together for more space. Leave edible willow toys in it for play and chewing. Bunnies adapt pretty well, so if you do not alter the routine too much on your days off, he should be ok. A pair is an idea, but I am concerned that it would be harder to train two to adapt, at least at first. Bunnies make good working people pets because they will sleep when you aren’t there midday, so are not as lonely as you imagine. As long as you pay attention for a few hours morning and evening, it should be ok.